sorry if this has been done before: so I decided I want to write my own basslines, rather than just play the root notes of what my guitarist plays. and I need a little help. can some explain to me the 3rd and 5ths, and chromatics.? also, how do I know what key I am in? I still dont quite understand it. like heres an example: my guitarist is playing a bunch of D(open) and G notes on the 6th string. I want to play something on my B string. so I would fret my third fret for the D's. but I dont want to play G on my B string. what are my alternatives? can I play an E note on the B string? or would that not match the G note my guitarist is playing? like how do I find out which notes go with which notes? or, do I always have to play root notes? and I can only be creative with whats in between the root notes? when incorporating chromatics, can I use them to replace the root note of what the guitarist plays? or are they just to "approach" the root note? thanks. I hope my questions make sense.